Apparatus and method for measuring electrochemical and viscoelastic properties of a liquid
AssigneeExxonMobil Research and Engineering Company
InventorLimin Song
Life of this patent
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Abstract
An apparatus for measuring electrochemical and viscoelastic properties of a liquid includes two sensing components, an electrochemical impediance spectroscopy component and a quartz crystal microbalance component positioned within a housing for receiving a liquid for monitoring and arranged so that each component shares a common electrode. Means are provided to simultaneously apply a sinusoidal waveform across the electrodes whereby information on the electrochemical and viscoelastic properties of a liquid being monitored is obtained.
Claims12
A sensor for simultaneously monitoring the electrochemical and viscoelastic properties of a liquid comprising:
- an electrochemical impedance spectroscopy component (EIS) and a quartz crystal microbalance (QCM) component positioned within a housing for receiving a liquid for monitoring,
- the EIS and QCM components sharing a common electrode with the common electrode operatively connected to only one analyzer,
- the EIS component having an electrode spaced apart from the shared common electrode operatively connected to the analyzer defining a space to contain liquid received within the housing to be monitored;
- and
- the analyzer having means for simultaneously imposing an AC signal over a range of frequencies on both the EIS and OMS electrodes and measuring simultaneously the electrical response to the imposed signals whereby the electrochemical and viscoelastic properties of the liquid is monitored.
A sensor for simultaneously monitoring the electrochemical and viscoelastic properties of a fluid comprising:
- a housing in which is positioned a quartz crystal having a top electrode and a bottom electrode;
- spaced apart from the top electrode is a third electrode defining a space therebetween for receipt of fluid to be monitored;
- mean for applying an AC signal to the electrodes and for measuring the electrical response to the applied signal whereby the electrochemical and viscoelastic properties of the fluid are monitored.
A method for monitoring the condition of a lubricant comprising:
- passing the lubricant into contact with two spaced apart electrodes, one of the two electrodes being part of a quartz crystal microbalance, the quartz crystal microbalance having a second electrode;
- simultaneously applying an AC signal to the electrode at any two of:
- the mechanical resonance point, Pr, and half power points, P1 and Pu, at which the vibration power of the crystal is half that of its resonance;
- simultaneously measuring the electrical response to the applied signal with only one analyzer;
- determining the conductance an susceptance from the electrical response;
- and
- comparing the measured conductance and susceptance to predetermined conductance and susceptance values whereby the condition of the lubricant is monitored.
Dependencies are inferred from the claim text.